Process of and apparatus for distilling hydrocarbons under pressure



Dec. 14, 1926. 1,610,523

. I F. My. HEss y PROCESS @E AND APPARATUS EUR UISTILLING `HYDROcPEBoN's UNDER PRESSURE Filed June 7; 1922 4 sheets-sheetA 1 De@o 14, 192e.

F. M. HESS PROCESS OF AND APPARATUS FORDISTILLINGHYDROCARBONS UNDER PRESSURE 4'sheets-shee-a 2 Filed June 7 1922 m55/000W Tan/fr- M. Mms l EROCESS OF AND APPARATUS FOR DI STILLING HYDROCARBONS UNDER PRESSUREy .05 A 3 65 @WV PROCESS OF AND APPARATUS FOR DISTlLLING- HYDROCARBONS UNDER PRESSURE my: m

Patented Dec. 14, 1926.

@UNITED STATES PATENT OFFICE.

lFRANCIS M. nnss, or WRITING, iupIANA.

Application filed June 7,

My invention relates to ,an improved process of and apparatus for distilling loils under pressure, involving an. operation commonly known as cracking by which a `Igreater volume of lower boiling point hydrocarbons is produced than is obtainable by ordinary methods of distillation. 'The successful cracking of oils under pressure involves two major problems; 'and the degree to which these two problems are solved determines' the eiicencv -and economy of the` process itself. The :[irst of these problems is to ei'iciently and economically crack a'portionof the oil; and the second is to eiect a clean separation of the portion cracked and the portion that will not crack at the operating temperature and pressure. In' .the solution of the first problem it is 1. essential to avoid local overheating in order 'i Y20 to prevent excessive coke formations which constitute the greatest obstacle and hindrance in all known cracking systems of oil distillation. The prevention, or at least the substantial reduction, of coke formation is, in my p-resent invention, brought about partly by effecting an exchange ofv heat from the distillate produced andthe residuuin drawn oil' to the crude material so that the additional heat required of the primary heating medium is reduced to a minimum, thereby avoiding local overheating; and partly by employing a heating system that causes the crude material to be heated in a progression, whereby the heating strain is so reduced and distributed and the intensity of th-e heat required is so lowered that only ing when required.

a negligibleamountof coke is produced.

Furthermore, in my present apparatus practically all of the carbon or coke that is'gena erated in the apparatus is deposited on the surfaces of certain heating plates in the boiler or still over which'the crude material iiows in the form of a wide thin film, washing the carbon or coke off practically as fast it is deposited. Moreover the boiler or still is of such a construction as to render the heating plates easily accessible for clean- 4In carrying out my invention, I pass the -vapor given off from the. boiler or still first through a dephlegmator` and thence through a vapor condenser. In the dephlegmator and condenser the reflux-and vapor impart their ylatent heat of vaporizatioii to the incomng oil, which latter travels countercurrent to the flow of the vapor in both the 1922. serial No. 566,470.

condenser and the dephlegmator, so that there is a gradual exchange of heat in regular progression from the vapor to the crude material; the condensed 'vapor or distillate first encountering the unheated oil, and the latter being progressively and uniformly heated up as it trav-els through the inci'easingly heated portions of the vapor eon-l denser and dephleginator. Not only does the inflowing o"l thus absorbthe heat of the vapors in the manner described, but it `likewise absorbsheat from the residuu'm of the stillwhich is caused to flow, under the:A

pressure maintained in the system, through the dephlegmator and vapor condenser in the-saine direction as the vapor counterof heat from the vapor.

In the accompanying drawings I have illustrated a complete apparatus capable of carrying out my improved process of oil cracking and embodying in a practical and preferred form the novel structural features of my present invention; and referring theret0 thereby absorbing aV` still `further amountl 1 is an elevation, partly in v l`vertical section, illustrating a complete planv or system embodying my invention:

through the still;

Fig. 3 is an enlarged vertical section through the dephlegmator and condense-i' and their. immediately associated parts and iow of the reflux is effected;

Fig. 5 is a cross section on the line 5-45y of Fig. 4;

Fig. 6 is an enlarged horizontal sectionl Fig. 2 is an enlarged vertical isection.

through the still taken onthe line 6-6 of' 'I Fig. 2;

Fig.

a pair ot heating plates taken on the line 7-7 of Fig. 2;

7 is an enlarged-cross section through Fig. 8 is an enlarged cross-section through i the dephlegmator and'vapor 'condenser taken' .on thet line'8-8' of Fig. 3

Fig-9 is a vertical section o a device for fixing the level of the condensate -in the condenser; and y Fig. 10 is an enlarged'cross-section on the line 10-'-10 of Fig. 9

I will. irst brieiiy describe the principal units of the completesystem andv their connections, and I will then describe in detail the several units themselves.

Referring to Fig.' 1, R designates a residuu/in tank of ample capacity and mounted on a suitable foundation, said tank being capable of'sustaining an internal pressure ofanywhere from one to one thousand '.pounds' per squareA inch gauge pressure. On this tank is mountedthe boiler or still designated 'as an entirety by S. 4Froiiithe top of the still coaxially disposed pi es 10 and 11 lead into the bottoml of a' ephlegmator and *scrubberv designated as an entirety lby D.

f condenser. From' the upper. portion of' this by a centraltube through -Whichth'e re-y lsiduum flows from the bottom of the stilil `5.5 directly into the .rsiduum tank. Mounted latter a pipe l5 conducts the oil'into the top ot an oil tank T, equipped with a float valve 99 from the lower end of which tank a'pipe 16 carries-the oil into the dephlegmator D.

From the bottom of the condenser C pipesy nerwall of the headerV and are fitted into 17 and 18 convey the condensedrdistilla'te into a receiving drum Z from the upper'end of 'which the permanent gas is released through a pipe 19 and cock 20, and-from thev lowerend ot whi'h the distillate. flows to storage through a pipe 21 and cock 22. ,Y

. Thema. 'y p i AThe boiler-orstill is mainly illustratedas to its structural details in Figs. 2, 6` and 7. 23 designates. the lower head of a cylindrical metal tank constituting `the housing or shell' of the vapor generator. This tank head 23 may conveniently bemounted and supported directly on the residuum tank R by suitable:

feet 24, and communicates with 'said' .tank

on the tank head 23 lare a pair of arallel "upright frame' structures designate ...asygan entirety by 26, whichconstitutelsupports for a pair of (left and right joined at their convergent ends by hollow headers and internested .so as to form' be-l tween adjacent plateso the two groups aflow of the crude material in a'broad thin tom. Fig. 2 Alhave designated the left f hand group as an entirety by 1- and the right hand group lwhich interiits therewith .as an entirety hy-.7'. The heating plates vof both groups are structurally identical and are best -shown in` detailv in the crosssectional views,

Figs. 6 and 7', wherein 27 designates a group of `tubes disposed side by side Aat equally spaced intervals, and 28 designates each ot a pair of longitudinally corrugated boiler plates which overlie and underlie respectively the tubes 27, and 29 designates rivetsunit- 'in the two plates midway between adjacent adjacent tubes 27 and the plate sections span' ning adjacent tubes. Figs. 2 and 6 show one practical means of uniting the convergent ends ot' each connected pair of'heating plates so as to render the internal conduits ot' saidx plates continuous.- 30 designates a hollow header or manifold that extendstransversely of the inner convergent ends of the heat- 'I ing plates and is provided with a central" longitudinal partition or lbridge plate 31 f extending from end to end thereof, and' is further provided with a. tapped cleanout' holes 32 in its outer `wall normally closed by. plugs 33. .By vreference'to Fig. 'it will be observed that the 'header `30 carries trunnions 34 journaled in the frame uprights 26.

The tubes 27 are extended throughvthe iiithe .partition Wall 3l,`whereby ysaid tubes..`

communicate freely with'a' header chamber 30a on the'outer side ofthe partitionY wall; The inner vwall of the header 30 is `formed with apertures 35 at points betweenadjacent tubes 27, thus throwing the'heating plateY .conduits that lie betweenv adjacent tubes 27 into communicationA with a header 'chamber 30? on the inner s'de ofthe partition v3.1.

The outer convergent ends"of adjacent heater plates are placedfin lcommunication with each other by. ay generally similar header construction, comprising. individual headers 'oi; 'manifolds 30. structurally identical with the headers or manifolds 30, andhaving their .rsiective inner and outer chambersconnerte in'Fig. 6, thel headers 30 have at their ends v .truimions 38,-similar.to the trunnions 34 of vthe. h'eaders'30,.which trunnions 38 are like- A wise mounted land 'supportedin the upright enerally .VV-shaped groups.,

of hollow heating plates y; vcrtilcalftubes 36- and 37. As shown frame' 26;- '1

continuous zigzag ymultiple tube conduit for the upward flow 'of a heating agent through the heating platet'ubes27, 'thelieader compartments 3.0, and thepipes 37, and another continuous multiple tubezigzagj conduit ttor lfilf From the correspon the upward iow of another heating medium through the passages-formed by and between the tubes and the boiler plates, the header compartments 30, and the pipes 36.

' In preferred'practice the last mentioned multiple tube conduits are used for the upward flow Fofthe primary heating medium, which is prelfeiably superheated steam, while the first m itioned group of conduits is employed for the upward iiow of residuumfrom the-residuum tank R. To insure the vdownward and forward flow of the crude material, the longitudinal edges of each plate which forms a part of the trackwayor Ipatho'f the material are turned upwardly, as show-n at 39 in -F ig. 7 to a level slightly abovethe height of the headers, thus preventing,lateralspilling or overliow of the crude material, and insuring its continuous downward flow in a zigzag direction over the header at the footof the plate down onto the next underlying heating plate.

The apparatus last described, consisting 40i. the internested generally W-shaped hollow heating plates with their connecting headers and pipes, is vsubstantially identical with that shown. described and claimed in a former application filed by meen the 29th day of April 1922` Serial No. ``557,421, and no claim thereto specifically isfmade herein.

Surrounding and completely enclosing the vapor generating apparatus last describedis a cylindrical .tank or bell, comprising a tank body 46 and an upper tank head 41 which may be integralor continuous with the body 40, and is so shown herein.l The lower tank head 23 andthe tank body 40 have mating flanges 23 and 40 '(Fig. 2) providing a packed tongue and groove joint at 42 and united by boltsor rivets 43. The still-housing or tank is, of course, constructed of a'material capable of withstanding the maximum internal pressure under which the system may bepperated and which Icontemplate may approximate insome instances one thousand pounds per square inch.

Fromthe' outer chambers of the lowermost headers-30 ofthe two groups of heating plates there extend downwardly pipes 44 (Fig. 2) through the lower tank head 23 and the top of theresiduum tank' R, said pipes 44 terminating slightly above the bottom of the residuum tank, and serving to.

lead to the inner chambers of the two lower-` most headers 30 and from the corresponding chambers of the topmost headers 30 branch pipes 50 conduct the steam to a sinl glei steam discharge pipe 5 1 that is carried Vthrougnthe head '41 of the still tank.

Thesaid top 41 of the still tank has a central vapor outlet opening 52, through and over which is fitted a shortpipe section 53 carrying a coupling orunion 54, to which latter is connected the pipe .1f) previously described as enclosing the resid-num pipe 11.

Directly beneath the pipe section 5 3 is a :tunnel 55, through which the incoming crude material, together with the reflux, is 'delivered to and overilows the trough 56 extending crosswise of the topmost heating plate, by which the crude material overflows onto the latter.

The alephlegmazor. i

i The detailed structure of the dephlegmator is shown mainly in Figs. 3 and 8. This comprises a cylindrical tank body 57 and lower and upper heads 58 and 59 joined to 'l the tank body by tongue and groove joints as shown. This tank is divided by transverse `tube sheets or diaphragms 58and 59v into upper, intermediate and lower compartments 60, 61 and 62, respectively. Extending between and at their ends rolled into the diaphragms 58 and 59 are several circular groups of vapor tubes 63` through which the vapors from the-still iiow from the lower compartment 62 to the upper compartment 60. The Avapor scrubbing and condensing effects of thetubes 63 may be enhanced by equipping each tube with a spiral64, clearly shown in detail in Figs. 4 and 5, by which the vapor flowing upwardly through the tube is caused to follow a serpentine path.-

Inwardly ofthe innermost group of vapor tubes is disposed a similarv circular group of tubes 65 which constitute residuuin conducting tubes. To the lower diaphragm 59 is secured a large tube section or manifold 66 that encircles and communicates with the lower endsof .the residuumtubes 65; and the manifold 66 is connected by a p i e 67 and unionl coupling 68with the resic num How pipe 11 from the still; and the bottom '58 of the dephlegmator tank is con'- neeted by a pipe 69 and flanged and bolted coupling 'ZO with the the top of the still.

'Interposed in the pipe 10 is a flanged T- coupling 10 from the upper side ofvwhich vapor conducting pipes 71 and 72 lead into the upper portion of the lower compartment 62 preferably at diametrically opposite points of the latter.

Fitted into and depending from'thelower diaphragm-59 .and communicating with the', intermediate chamber 61 is a pipe 73 for the discharge ofthe crude material from the inpipe 10 leading fromy termediate chamber 61 to the lowermost chamber 62; and in this pipe73 is a regulating valve 7 4 having a -stcm 7 5 extending through a packed bearing in the cylindrical wall of thc dephlegmator tank, by which the ilow ofthe crude material can be regulated as hereinafter described.

Secured tothe upper diaphragm 58 and encircling the upper ends of the residuum tubes 65 and communica-ting with the latter" is a large pipe section or manifold 76, similar to the manifold 66; and extending laterally therefrom is the residuum delivery pipe compartment 60 and itscontained manifold 76, into and nearly to the bottom of the intermediate compartment 61. Preferably and as herein shown, the lower end of the pipe 8() is closed, and said pipe is provided with pcrforations or small apertures 81 that extend practically the full length` vot that portion of the pipe lying within the chamber 61 and allow the incoming oil to trickle through and build up in the space around the vapor and residuum tubes. In the upper end of the pipe is a 'valve 82 having a' y stem 83 by which the amount of oil entering the perforated pipe 8O may be controlled at will.

The condenser.

From the'dephlegmator last described the uncondensed portion of the vapors Vand the uncondensible gases flow through the pipe 12, and the residuum Hows through the pipe 18, to the condenser C. structurally the condenser is substantially a duplicate of the dephlegmator, omitting the `perforated 4oil delivery pipe 80, Awith the vapors and residuum flowing from top to bottom, 1nsteadof in the reverse direction. Briefly describing the structure of the condenser, the same comprises a cylindrical tank bodyk 84 andlower and upper heads 85 and 86 joined to the tank body by the tongue and groove joints shown. by transverse tube sheets or diaphra ms 87 and 88 into upper, intermediate an lower compartments 89, 90 and 91, respectively.

.Extending between and lat their ends rolled into the diaphragms 87 and 88 are several `circular groups of vapor tubes 92, through which the uncondensed vapors and uncondensible gases from the dephlegmator How.

' from the upper compartment 89 to the lower compartment 91.

Inwardly of the innermost group of vapor tubes is disposed a group of tubes 93 which The tank is divided' residuum tubes 93, and into which the residuum conducting pipe 13 is led. The

Ivapor conducting pipe 12, which encircles the residuum pipey 13, is similarly connected into the side of the upper `compartment 89.'

encircling the lower ends of the residuum Securedv to the lower diaphragm 88 andv tubes 93 and communicating with the latter is alarge pipe section or manifold similar to the manifold 94; and from the bottom of the manifold 95 a residuum discharge pipe 96 leads through the lower head 85 of the condenser cylindergand thence to anysuitable point of discharge'or storage. In the pipe 96 is a flow regulating valve 97 (Fig. 1) having a stem-98 by which it may be' manually manipulated.

-From the lower end of the condenser tank the distillate passes by the pipes 17 and 18 into the receiving drum Z, as already' described.

The pipe 14 through which the crude material enters the system leads into the intermediatecompartment 9.0 substantially at the lower end of said compartment; and the incoming crude material completely fillsv said intermediate compartment surrounding and being heated'by the vapor and residuum pipes, and from a point near the upper end i of said compartment lflows through the pipe 15 into the upper end ofthe tank T, the level ingwhich latter Kis maintained constant by a float vcontrolled valve 99 (Fig. 1).

Inorder to maintain a predetermined or desired level' of the condensate in the condenser. C the same isxpreferably equipped with a leveling device similar to that disclosed in my former application Serial No; 557 ,421, hereinabove referred to,'and also' disclosed and claimed in another application filed by me on the 29th. day -ofDecemben 1921, Se- Iii rial N0. 525,597.^"'- Briefly describing the said leveling device, `the Vvertical drain pipe 18 with which thehorizontal drain pipe 17 communicates .extends (to a considerable height above the. pipe;17 and opposite the condenser Cl The pipe 18 is provided with a partition v100 slightly/.below the junction of the horizontal pipe 17, in which partition-is slidab'ly mounted a tube 101 having an open upper end, as shown in Fig. 10, carrying a spider 102,` in the hub o f which is swivelled Ythe lower end of a screw-threaded rod 103, this latter extending upwardly through and in threaded engagement with a head or cap 1041011 the upperend of the pipe18 and equipped witha handwheel for turning the same. By raising'an'd'lowering the overflow-tube 1101,-, the upper open end of the latter establishes thelevel of the liquid in the condenser in an obvious manner.

a cock 106 and also with a check valve 107l is forced by a pump `froman outside source throughline 14 past check valve 107 into the intermediate chamber of condenser C tllling the space around. the tubes of the latter.

Thence the -oil ,continues upwardly through line l5` past float valve 99 into the overflow tank T,- yin which -a constant level is mainy 'tained.- From tank T the oil Hows by gravitythrough pipe 16, and by manipulating '.valve.. 82 the amount entering the perfo- 'rated pipe 80 is controlled at will. The perfo'iations in said pipe allow the incoming oil totr'ickle therethrough and buildup around heg-'vapor ,and residuum tubes in' the interi `,Irvie'Sd-iate chamber, so that the coldest portion is onv top and the hottest portion is at the bottom,. with the body of oil moving from -top to bottom counter-current to the upward traveliof the vapors and residuum. From Athe'bottom of the intermediate chamber of fighe dphlegmator Athe.oil flows throughpipe 3.

Sintothe bottom,y chamber'62 of the dephlegmator. With a constant flow'entering through pipe 80, the height of oil in the intermediate chamber of the dephlegmator may be controlled at will by means of the regulating valve 74. This. in turn determines the time required for the oil to pass through the chamber,- or, in other words, the length of p time it is incontact with the vapor and residuum tubes,`which, in turn, controls the amount of relux dropping out of the vapors In the compartment (S2-the feed oil mixes with the reflux from the vapors, and the mixture flows through the pipes 69, 10, and 53, and funnel'55 and overiiow trough 56 onto the iirst heating plate. Flowing back and forth over the several heating plates, the reuX is again vaporized together with such portion of the crude oil as will'vaporize at the operating temperature and pressure.- From the bottom of the still the residuum tlows through pipe into tank R.

Since there is a wide range of tempera-- ture increase from the top heating plate to the bottom heating vplate and the vapors released from the upper plates are forced to mingle in the samechamber with the Avapors released from the bottom plates, the former are heated by the latter 'far above their vaporizing temperatures, whichheating aids ytheir QrCkDg to the lower boiling points,

between the top and the bottom of the still,

and that there has been a clean separation of vapor and residuum with the latter removed, and that constantly there is added to this mass of vapor the additional vapor from reflux that was previously partially cracked, an ideal Ycondition to assist in cracking is presented. It should also be noted that this cracking zone is attended with a continued retrogression of temperature creating a continual scrubbing in an upward direction.

The residuum is forced upward from the tank R by the pressure maintained on the latter and, after passing through the resid-- uum conduits of the heating plates, leaves the still through pipes 45, 46 and 11 which are enclosed within the vapor line. T hence the residuum follows a path within and parallel to the path of the vapors to the bottom of condenser C, and is lowered in temperature in the' same manner as the vapors. namely, by giving'up its heat to the infiowing oil traveling counter-current thereto.

The vapors from the still flow through the upper portion of pipe 10 and the branch pipes 71 and 72 into the bottom chamber 62 of the dephlegmator, whence they travel upwardly through the vapor tubes 63. following the circuitous paths created therein by @the spirals; during which travel a portion of the vapors is'condensed and ydrops backwardly into the chamber 62. By raising or lowering the level of the oil around the tubes ythrough manipulation of the regulating valve 74, the amountof retiux dropping out ofthe vapors is increased or decreased. This controls the temperature of the-vapors emitted from the dephlegmator, and thisin turn determines the boiling range of the distillate produced.

The vapors traveling through line 12 over ins into the condenser continue downwardly I' through the tubes 92 of thel condenser in which they are cooled and condensed by the crude oil traveling upwardly, with the aid of the leveling device which increases or decreases the condensed liquid level in the condenser. Flowing out of the'bottom of the condenser through lines 17 and 18, thedistillate continues downwardly into the re'- Ceiving drum Z. From this latter the dis'- l" all of the heat in the distillate,producedl and residuumdrawn 0H is transferred advantageously .to the crude material. ylatter at al1 times is'traveling counter-current to the distillate and residuurn and at This all times is in close proximity to extract tank by the How of the oil. Thus all fire hazards that are caused by local overheating with direct tire are entirely eliminated .in

the present system. Any coke deposited'on and adhering to the upper surfaces of the' heating plates-of the still is easily removed by disconnecting the pipe lines at the top of the still and stripping the tank or bell Oii the stack of heating plates so that acces to y,

the latter is readily had. l

The cracked vapors flow through a continuous passage that is constantly decreasing in temperature all the way-from the bottoruI of the still to the top of the dephlegmator.

This creates an ideal condition for cracked vapor to be further cracked in. a continued decreasing temperature zone, with a long enough time interval elapsing :for reactions and equilibrium to be set up. It is a Well known fact in the art of cracking oil that it is not necessary to employ pressure to accomplish cracking. The heat alone does the cracking; but to .attain desirable distillates it is advantageous to employ pressure as aretarding agent; that is, to hold the vapors in the cracking zone and reaction zones long enough for desirable compounds to form. The higher the pressure, the better the control, and the lower the boiling point of the distillate becomes. In addition, first it is de'firable to heat in a progression in the cracking chamber. allowing the vapors to rise and diffuse in the cracking zone. In my still the hottest vapors are at the bottom and the coldest at the top. Therefore, diffusion of vapors takes place in a decreasing temperature zone. Secondly, in the reaction zonetdephlegmator) it is a distinct advantage for vapor to pass through a decreasing temperature zone. In my dephlegmator this condition exists, and as the vapors travel upward, the heavier portions are reluxed and drop down. creating a scrubbing effect. The vapor linally emitting from top of the dephlegmator is of a muehhigher temperature' than the average boiling point of distillate produced. Thus it is correct to state that said vapors are in a condition ont superheat, that is they are still fmuch higher than their own boiling point. Therefore, crack- .ing is taking place in the dephlegmator. Thirdlv,'it is quite essentiai that a long enough time elapse from the time the ,oil lis vaporized in the bottom of the still to the time it reaches the top of the reaction chamuher (dephlegmator) iter cracking reaction',

`and equilibrium to be set up, or the'distill'ate produced Will be undesirable ;l that is, itv will contain too large a percent of unsaturated compounds and Will not be of the proper boiling range, f

Finallythe apparatus is Well adapted'tov A ing the crude material throughv a still, sub-1v jecting the same insaid still to the heat of a 'disuuing hydrocarbons, under pressure 'to produce lower boiling point hydrocarbons,which consists in pass' iuid heating mediumandmesiduuin out of contactwith both of vthe latter, said heating medium and residuum being n laintainedoutQ4 returning the reHuX from said'dephlegmator 'Ito said sti1l,fand passing the uncondenseld' vapors from said dephlegmator to a con'- denser.

2. A process of distilling hydrocarbons under pressure to produce lower boiling .point hydrocarbons, which consists in passingthe crude material successively through a vapor condenser, a dephlegmator and a still, simultaneously passing the residuum from said still through the dephlegmator counter-current to the ioW of the crude material and out of contact with the latter, passing the vapors generated in -said Still into said dephlegmator, and passingthe uncondensed vapors from said dephlegmator to said condenser.

3. A process of distilling hydrocarbonsV under pressure to produce loiver boiling point hydrocarbons, which consists in passing the crude material successively through a vapor condenser, a dephlegmator anda Still, simultaneously passing the residuum from said still through the dephlegmator and the condenser counter-current to the flow of the crude material and out of contact with' the latter, passing the vapors generated in said still into said dephlegmator, and passing -the uncondensed vapors from said dephlegmator to said condenser.

4. A process of: distilling hydrocarbons under pressure to produce lower boiling point hydrocarbons, which consists in passing the crude material successively through a vapor condenser, a dephlegmator, andY al of contact with the latter, passing the vapors mater, and passing the uncondensed vapors generated in saidstill into said dephleg- ,30111 said dephlegmator to said condenser. 13

5. A process of distilling petroleum' hydrocarbons under pressure to produce lower boiling point hydrocarbons, which consists in passing the crude material in a continu-- ous tlowA successively through a vapor con.

denser, a dephlegmator anda still, simultaneously` passing the residuuni from said still through the latter, lthe dephlegin'ator and the condenser counter-current to the liow oit' the crude material and out of contact with the latter, regulating the volumel of crude material in the dephleginator to produce distillates of the desired boiling point, passing the vapors Agenerated in said still into said dephlcginator, passing the uncondensed vapors from said dephlegmator to said condenser, and comxningling the reflux fromthe dephlegmator with the crude material ioiving from the latter into the still.

A6. A process of distilling hydrocarbons under pressure to produce lower boiling point hydrocarbons, which consists in passing the crude material successively through a vapor condenser, a dephlegmator and a still, simultaneously passing the residuum I from said stilll through the latter, the dephlegmator and the condenser counter-cur rent to the lflovvof the crude material and out of contact With the latter, passing the vapors generated in said still into said dephlegmator, passing -the uncondensed vapors from said dephleginator to said condenser,

controlling the volume of Aliquid condensate in said condenser to thereby regulate the amount of heat transferred tothe crude material and commingling the reflux from the dephlegmator with the crude material flowing from the latter into the still.k

7. A process of distilling hydrocarbons under pressure to produce lower boiling` I pointhydrocarbons, which consists in passing the crude material successively through a vapor condenser, a dephlegmator and a still, simultaneously passing the residuum from said still through the latter, the dephlegmator and the condenser counter-cur rent to the flow of' the crude material and out of contact with the latter, passing the vapors generated in said still into said dephlegmator, passing the uncondensed vapors from said dephlegmator to said condenser, con-v trolling the volumel of liquid condensate in said condenser to thereby regulate the amount of heat transferred to the crude material, regulating the volume ,of crude material in the dephlegmator to produce distillates of the desired boiling point, and v commingling the reflux `from thedephleg mator with the crude material flowing from the latter intoA the still.' l

8. In an oil cracking-system of hydrocarbon distillatiom'the combination of a still,

" a dephlegmator provided with conduits for .the separate iow of vapors and residuum .phlegmator, and a pipe surrounding said site direction, flow conductors connecting lconduit of said dephlegmator, and a pipe Vmator to the still.

therethrough in on'e direction and of crude material therethrough in the' opposite `direction, means for passing residuum fror'gsaid still to the residuum conduit of saidldeplileg'- mator, means for passing L the vvapors from saidv still to the vapor conduitV otfsaid ,del phlegmator, and means for 'passing Athefc'rfncle material and reflux :troni said -deplil'eI to said still.

9. In an oil cracking system of hyd" bon distillation, the combination of ai ill, a dephlegmator provided with conduits :for the separate `floiv of vapors and residtuiv'ml therethrough in one direction and of crude material therethrough in the opposite direction, a pipe ior conducting residuum from said still to the rcsiduum conduit of said dephlegmator, "and a pipe constituting a conduit for the vapor from the still to the dephlegmator and for the crude material and reflux from the dephlegmator to the still.

10. In an oil cracking system of hydrocarbon distillation, the combination of a still, a dephlegmator provided With conduits for the separate flow of vapors and residuurn`9O therethrough in one direction and of crude material therethroughin the opposite direc' tion, a pipe for conducting residuum from said still Ato the residuum conduit of said deresiduum pipe and constituting a conduit for the vapor from the still to the de'phlegmator i and for the crude material and reflux from the dephlegmator to the still.

ll. In an oil cracking system of hydrocarbon distillation, the combination of a still, a l dephlegmator provided With conduits :tor the separate flow of vapors and residuum therethrough in one direction an'd of the crude material therethrough in the oppositev direction. a condenser provided vvith conduits for the separate loW of vapors and residuumtherethrough in one direction and of crude material therethrough in the oppo- 1l() the vapor, residuumand crude material conduits respectively' of 4said dephlegmator and condenser, a pipe for conducting residuum from said still to the residuum constituting -a conduit for the vapor from the still to the :dephlegmator and for the crude material and reflux from the dephleg- 12. In .an oil cracking system of l1ydrocarbn distillation, the combination of a tank `for containingiesiduum` under pressure, 4a'

still having la residuumconduit' extending therethrough and communicating'with said residuun tank, a -ldephlegmator-fy provided with conduits for the separate flow of'val pors'and residuum therethrough in, one/direction and of the crude material therethrough in theopposite 'direct-ion, a-condenser vpro- -I vided withconduits forthe separate .flow of vapors and residuuni therethrough in one direction and of the crude material therethrough in the opposite direction, flow conductors connecting the Vapor, residuum and crude material conduits respectively of said dephlegmator and condenser, a pipe for conducting residuuin fromthe residuum conduit ot' said still to the residuumconduit of said dephleginator, and a pipe surrounding said residuuni pipe and constituting a conduit for the vapor from the still to the dephleginator and for the crude material and reflux Jfrom the dephlegmator to the still."

13. In a gravity How cracking system ot hydrocarbon distillation, the combination of a, still7 a dephlegmator located 'on a higher level than said stilLan oil 'tank located on a i higher level than said dephlegmatzor? and a vapor condenser; plpes for, conducting the crude material into said condcnser,' from said condenser to" said-ltanlr, and from said fresiduum fromsaid dephlegmator to said condenser, and valves for regulating the flow of the crude material into and 'from said dephlegmator.

FRANGIS'fM. 

